Vendor GiroDisc 370mm Rotors for GM Brembo 6-Pot Calipers

It takes a village to raise a kit. This one is TMC's very own. @Lukez pioneered the 6-piston CTS-V DIY for the Model S. Then @jesse_le prototyped a rotor with GiroDisc for the Model 3 and Y. These full-floating slotted GiroDisc rotors for the Model 3 and Y come in at 370mm x 34mm. This mirrors the rotor size on the Cadillac CTS-V, Corvette C7 Z06, and other GM performance vehicles allowing fitment of massive GM 6-piston Brembos. For comparison, the OEM Model 3 Performance 2-piece rotor measures in at 355mm x 25mm while the OEM 1-piece "Base" Rotor measures a paltry 320mm x 25mm.

The GiroDisc rotors differentiate themselves from other manufacturers with U.S. sourced iron and beautifully anodized U.S.-sourced 6061-T6 aluminum rotor hats. The hat is also 4mm thicker than OEM which helps clear the unique stepped hub of the Model 3 Performance and obfuscates the need for small wheel spacers. The GiroDisc is also a true 2-piece rotor allowing you to replace the rings without need to replace the hats.

OEM GM Brembo 6-piston Calipers​

The GiroDisc rotors allow you to mount OEM GM Brembos from a number of GM performance vehicles including the ATS-V, CTS-V, and C7 Corvette Z06. These are lightweight 6-piston monoblock aluminum calipers that are optimized for cooling, specified as "low drag", and are designed to fit under 18" wheels. They mount up to the OEM Tesla front knuckle by either drilling out your caliper mounting holes to accept M14 caliper bolts or re-threading the caliper to accept the OEM Tesla M12 hardware. The latter allows you to return the vehicle completely to stock.

Another benefit of the GM 6-piston Brembos is a wide assortment of available brake pads. If you have ever searched for brake pads for the stock Model 3 Performance calipers you know that the selection for this seemingly proprietary caliper can be somewhat limited. The GM calipers feature a standard FMSI D1405 pad shape which opens up pad options from $64 Centric OE replacement street pads up to $700+ Ferodo DSUNO race pads.

Ordering​

As these are a relatively new offering, GiroDisc requires a minimum of 5 rotor pairs to make a production batch. Pricing is $1,200 per pair with free shipping to the continental U.S. There is an approximate 4 to 6 week lead time from the batch order for fulfillment. There is already some interest in the next batch and my hope is that the demand is strong enough for these to become regular stock at Emotive Engineering.

... and introducing... The EmotiVetted GM 6-Pot Bolt-on BBK​

This is a full bolt-on affair which allows you to reuse your factory caliper mounting bolts (brake dust shield removal required).

Street Kit - $2,649

• CTS-V Calipers - Silver (or optional Yellow) - re-threaded to accept factory Tesla caliper bolts
• GiroDisc 370mm 2-Piece Rotors
• DBA SP500 Street Performance Pads - copper-free ceramic pads, low-noise, and low-dust. Everything an OE+ street pad should be.
• Spiegler Stainless Steel Brake Lines
• OE GM Caliper Hardware

Track Kit - $2,899

• C7 Corvette Z06 Calipers - Red - re-threaded to accept factory Tesla caliper bolts
• GiroDisc 370mm 2-Piece Rotors
• G-LOC R12 Track Pads - amazing pedal modulation, rotor friendly, at the expense of some noise and dust.
• Spiegler Stainless Steel Brake Lines
• OE GM Caliper Hardware

Not ready to go full on BBK? Emotive Engineering is an authorized GiroDisc dealer offering a full line of OE-replacement 2-piece rotors for your Tesla Model 3 or Y.

 

[Lindenwood]

I just got mine! Super pumped to get them mounted .

 

[TwoK4drSi]

Yay! It’s up and running again with a vendor on board

 

[Lukez]

Thanks for the shout out!
This upgrade is totally worth it. Even if you think your oem brakes are decent this will make a huge difference in safe stopping, even in every day driving. I couldn't believe the difference and I don't track/race I was doing it as a hobby.
The fact that they look kick ass is a cherry on top!

 

[gearchruncher]

This upgrade is totally worth it. Even if you think your oem brakes are decent this will make a huge difference in safe stopping, even in every day driving. I couldn't believe the difference and I don't track/race I was doing it as a hobby.

It's awesome we have options like this in the community, but let's not mislead. In a single emergency stop, it's all about your tires, and brake rotors make basically no difference. Heck. in your first emergency stop, carbon ceramic brakes have been proven to be worse than simple iron discs. Claiming these make a huge difference in safe stopping for road use is a bit over the top.

That is no knock on the product, and I really want a set for track use, but the stock brakes on Teslas are more than adequate for the street.

 

[Lukez]

It's awesome we have options like this in the community, but let's not mislead. In a single emergency stop, it's all about your tires, and brake rotors make basically no difference. Heck. in your first emergency stop, carbon ceramic brakes have been proven to be worse than simple iron discs. Claiming these make a huge difference in safe stopping for road use is a bit over the top.

That is no knock on the product, and I really want a set for track use, but the stock brakes on Teslas are more than adequate for the street.

Fair enough but I wasn't really talking about slamming on brakes while going fast, I was more talking about hitting the brakes at slow speed. I found the oem brakes very "squishy". Also after a rain the first time using the brakes the oem brakes didn't do anything for a good number of feet until the rust was gone.
Maybe my oem brakes were defective, but there was a clear difference.

 

[Lindenwood]

Has anyone figured out the minimum wheel barrel diameter for these? Just curious if any of the 18” that fit Performance brakes will fit over these.

 

[TwoK4drSi]

Has anyone figured out the minimum wheel barrel diameter for these? Just curious if any of the 18” that fit Performance brakes will fit over these.

Seeing that UPP has runs an 18” over 394mm you definitely need a full forged wheel with a thin barrel. Monoblock with a big concavity or drop cup center. It might sound bass awkward but having a larger diameter “helps” bc the caliper is farther away from the center in turn making caliper to spoke clearances greater as you move away from the center.

Here’s a starting point on 19” wheels that fit a 394mm if that helps. You are 12mm less radius which equals to about 1/2” which should give you an 18” barrel. Wheel weight placement is probably key so it doesn’t impact the caliper. The wheels listed are flow forged so you should be golden with full forged.

 

[emotiveeng]

18" APEX EC-7

I have to caveat this with the fact that this is on the ground since the shop car's front suspension is currently torn apart. You can see the studs are not 100% lined up, but my guess is there's going to be in the range of 15 to 20mm to the barrel. There's about 30mm from the caliper to the spoke. (Apologies for the brake dusty photo.)

 

[stevehifi]

awesome post and thanks for supporting the enthusiast model 3 community.

any chance your kit with corvette calipers can be offered re-painted with TESLA logo? This would really sweeten the offering as a fully
bolt on and aesthetically ready kit that looks and operates almost as Tesla branded offering. Would even be open to no logo at all.

 

[emotiveeng]

any chance your kit with corvette calipers can be offered re-painted with TESLA logo? This would really sweeten the offering as a fully
bolt on and aesthetically ready kit that looks and operates almost as Tesla branded offering. Would even be open to no logo at all.

Absolutely an option that is being looked at inspired by some other setups in a previous thread. Have some parts being sent to a local powdercoating shop next week to sample their work.

 

[Snelson3]

Great to see this got picked up by a vendor. I’ve been on the list with Girodisc hoping others would also reach out to them to fill up the 5 people.

One question - for the brake lines, will your offering be different than the MPP lines?

 

[Fzdog2]

I've had these installed for a few weeks, I was part of the first round.
So far all 3 sets of 18" wheels I have fit. 18x9.5 Apex EC-7R, 18x8 TRMotorsport C4 (Pic attached), and 18x10.5 Konig Hypergram (Pic Attached)

 

[jesse_le]

@Snelson3 - I’m working with Essex/Speigler on custom lines for this setup.

 

[yjypm]

What are the piston sizes of this caliper?
Proper piston sizes needs to be considered to maintain brake bias. Stock M3P piston sizes are 4x 42mm, total piston area is 55.4cm^2, since max brake fluid pressure when brakes are applied stays the same stock vs bbk, braking force (which equals fluid pressure times piston area) is direct proportional to piston area. Considering the brake rotor sizes (370mm vs 355mm, braking torque equals braking force times the average radius of the rotor where it makes contact with the pads), according to my calculation, the piston area on this 6 pot caliper has to be around 52-53cm^2, preferably between 51cm^2 to 54cm^2 to maintain roughly the same brake bias front and rear.
Let's say the 6 pot caliper has 2x (small piston size A, medium piston size B, large piston size C, sizes in millimeters), total piston area is 2*Pi*((A/2)^2+(B/2)^2+(C/2)^2).

 

[Sam1]

What are the piston sizes of this caliper?
Proper piston sizes needs to be considered to maintain brake bias. Stock M3P piston sizes are 4x 42mm, total piston area is 55.4cm^2, since max brake fluid pressure when brakes are applied stays the same stock vs bbk, braking force (which equals fluid pressure times piston area) is direct proportional to piston area. Considering the brake rotor sizes (370mm vs 355mm, braking torque equals braking force times the average radius of the rotor where it makes contact with the pads), according to my calculation, the piston area on this 6 pot caliper has to be around 52-53cm^2, preferably between 51cm^2 to 54cm^2 to maintain roughly the same brake bias front and area.
Let's say the 6 pot caliper has 2x (small piston size A, medium piston size B, large piston size C, sizes in millimeters), total piston area is 2*Pi*((A/2)^2+(B/2)^2+(C/2)^2).

Good thing I'm bad at math, or I may show some type of concern for this theoretical observation.

 

[P3D-R]

Seeing that UPP has runs an 18” over 394mm you definitely need a full forged wheel with a thin barrel. Monoblock with a big concavity or drop cup center. It might sound bass awkward but having a larger diameter “helps” bc the caliper is farther away from the center in turn making caliper to spoke clearances greater as you move away from the center.

Here’s a starting point on 19” wheels that fit a 394mm if that helps. You are 12mm less radius which equals to about 1/2” which should give you an 18” barrel. Wheel weight placement is probably key so it doesn’t impact the caliper. The wheels listed are flow forged so you should be golden with full forged.View attachment 844434

lol, those pics look familiar. hehe.

 

[P3D-R]

@Snelson3 - I’m working with Essex/Speigler on custom lines for this setup.

The spiegler lines lack a bracket. We do a lot of the AP essex kits and have to toss those lines out because there's no bracket. It's very hard to pull them off the factory lines as well. I don't know if they created new ones or not but might be easier to just get with goodridge or a company that is already making the Model 3 lines.

 

[terranx]

Fair enough but I wasn't really talking about slamming on brakes while going fast, I was more talking about hitting the brakes at slow speed. I found the oem brakes very "squishy". Also after a rain the first time using the brakes the oem brakes didn't do anything for a good number of feet until the rust was gone.
Maybe my oem brakes were defective, but there was a clear difference.

Probably the pads more than anything else

 

[terranx]

What are the piston sizes of this caliper?
Proper piston sizes needs to be considered to maintain brake bias. Stock M3P piston sizes are 4x 42mm, total piston area is 55.4cm^2, since max brake fluid pressure when brakes are applied stays the same stock vs bbk, braking force (which equals fluid pressure times piston area) is direct proportional to piston area. Considering the brake rotor sizes (370mm vs 355mm, braking torque equals braking force times the average radius of the rotor where it makes contact with the pads), according to my calculation, the piston area on this 6 pot caliper has to be around 52-53cm^2, preferably between 51cm^2 to 54cm^2 to maintain roughly the same brake bias front and rear.
Let's say the 6 pot caliper has 2x (small piston size A, medium piston size B, large piston size C, sizes in millimeters), total piston area is 2*Pi*((A/2)^2+(B/2)^2+(C/2)^2).

The C7 calipers have pistons of 30, 34, and 38mm. Overall area will be 0.08% less than the stock M3P pistons (so basically negligible difference). Bias will shift slightly forward due to the larger rotors. It won't be enough of a difference to create a truly measurable performance difference.